Safety attachment for pneumatic devices



Aug. 10, 1954 A. G. FORD 2,685,874

SAFETY ATTACHMENT FOR PNEUMATIC DEVICES Filed Nov. 8, 1951 INVENTOR.

ADRIAN G. FORD ATTORNEY jby nearly all industries;

Patented Aug. 10, 1954 UNITED STATE PATENT OFFICE SAFETY ATTACHMENT DEVIThis invention relates generally to pneumatic pneumatic riveters,hammers, chisels, etc. More particularly, this" invention relates to asafety attachment for pneumatic devices. 7

Pneumatic devices of many types are employed This invention is primarilyconcerned with'those pneumatic devices which can be carried from placeto place by the operator and which weigh between about 20 and 50 pounds.Such devices are employed when it is impractical or impossible to removethe object to be worked upon to a machine shop. These types of devicescan be adapted to perform a varietyof functions, such as riveting,hammering, chiseling, chipping, cutting, or gouging metal or refractorysurfaces. Y, I

A pneumatic device of this general type is shown in Figure Iand,.although the instant invention is by no means limited to thisspecific tool, the invention oan be aptlyillustrated thereby. In FigureI, l is the tool shaft which -.is to directly perform the work upona-.desired object and'one end of this tool shaftzextends A within thehousing chamber $2.; ,A conventional motor mechanism (not shown) locatedwithin housing chamber 2 imparts periodic hammerlike blows to the end ofthe tool shaft I, which is within the housing chamber 2. These blows arein turn transmitted to the opposite end of the tool shaft which is toperform the desired work. In operation, therefore, the tool shaft 1 iscaused to move in and out of the housing chamber in a continuouspulsating manner. The motor mechanism is usually actuated by highpressure air admitted through line 3 when the operator manipulates thetrigger switch 4. The tool shaft I can be easily inserted or withdrawnfrom housing chamber 2 at any time since this shaft is not rigidlyfastened to any portion of the housing chamber.

Although pneumatic devices of the type discussed here are portable asopposed to being fastened in one particular location, they arenevertheless heavy enough that the operator needs to grasp the devicewith both hands in order to properly perform the desired work. Forinstance, as is illustrated in Figure I, when cutting or riveting avertically disposed metal surface, the left hand is usually placed inthe position shown to support part of the weight of the tool and toguide the tool shaft to the exact spot which is to be worked upon. Thetool shaft itself is usually composed of a high quality metal ormetallic alloy of the appropriate thickness,

FOR PNEUMATIC CES Adrian (3}.Ford, Drexel Hill, Pa., assignor to TheAtlantic Refining Company, Philadelphia, Pa., a corporation ofPennsylvania Application November 8, 1951, Serial No. 255,479

3 Claims. (Cl. 125-433) but it occasionallyhappens that a severe orsudden stress upon the shaft will cause the shaft to break. Since theoperator must necessarily exert some force upon the handle of thepneumatic device while'it is in operation, a sudden unexpected break inthe tool shaft will almost always result in. an immediate uncontrollablelurch of the entire pneumatic'device toward the metallic surface beingworked upon. When this occurs, the operators left hand will be crushedbetween the left handextremity of the housing chamber and the metallicsurface being worked upon. Such accidents are particularly dangerous ifthe tool shaft breaks at the point where the operator has placed hishand since there is a good possibility that the hand will be impaledbetween the broken end of the shaft and .the area being worked upon.

Such a hazardous condition is highly undesirable and it is therefore anobjectof this invention to provide a safety attachment which willprotect the handsof the operator in the event the tool shaft breaksduring operation.

. compassed within the scope of the instant invention is shown in FigureII. In essence this safety attachment 5 comprises an envelope ofelastomeric or rubber-like material, preferably oil resistant natural orsynthetic rubber. The safety attachment may be cylindrical or conical inshape, or partially cylindrical and partially conical as is shown inFigure 11. The safety attachment may be of any desired thickness,although it has been found that a 1% inch thickness affords a goodcushioning effect, long durability, and permits easy assemblage andremoval from the pneumatic device. One end of this attachment fitssnugly over one end of housing chamber 2 and the other end of theattachment fits snugly around a portion of the tool shaft i. This safetyattachment may be constructed so that it will cover any desired portionof the tool shaft 2, but it is only necessary to cover that portion ofthe tool shaft upon which the operator might place his hand. When thepneumatic device is being cleaned or repaired th safety attachment canbe quickly and easily removed since it is only retained in position bythe elasticity which it possesses. Holes or perforations appropriatelylocated in the safety attachment, such as those shown as 5 and I inFigure 11, are highly desirable since they facilitate installation andremoval of the safety attachment by avoiding suction and vacuum effects.

It has been found that when these safety attachments are employed inconjunction with pneumatic devices, accidents due to crushed fingers areentirely eliminated. When the tool shaft breaks, with the concomitantunavoidable lurch of the pneumatic device toward the area being workedupon, the rubber safety attachment absorbs the force of the forwardmovement of the device against the area being worked upon, so that atworst the operators fingers are merely gently pinched between rubbersafety attachment and the area being worked upon, rather than beingmashed or crushed as was heretofore the case.

Although the drawings and the above specification disclose a highlysuitable mode in which I have contemplated embodying my invention, Idesire in no way to be limited to the specific details of suchdisclosure, for in the further practical application of my inventionmany changes in the shape and construction and configuration may be madeby those skilled in the art as circumstances require or experiencesuggests without departing from the spirit of the invention within thescope of the appended claims.

I claim:

1. In a manually supportable pneumatic device comprising a tool shaft, anon -reciprocating housing chamber which contains one end of said shaftand a motor mechanism to motivate said shaft, the improvement consistingof a safety attachment comprising an envelope of elastomeric rubber-likematerial having an opening in one end thereof of about the same shapeand cross-sectional area as the pneumatic tool shaft and an opening inthe other end thereof of about the same shape and cross-sectional areaas the housing chamber the latter mentioned end of said envelope beingin much tighter engagement with the area it surrounds than is the firstmentioned end of said envelope with the area which it surrounds.

2. In a manually supportable pneumatic device comprising a tool shaft, anon-reciprocating housing chamber which contains one end of said shaft,a motor mechanism to motivate said shaft, the improvement consisting ofa safety attachment comprising an envelope of elastomeric rubber-likematerial which envelops an areas between an intermediate portion of thetool shaft and a portion of the housing chamber the end of said envelopewhich surrounds a portion of the housing chamber being in much tighterengagement than the end of said envelope which surrounds a portion ofthe tool shaft.

3. In a manually supportable pneumatic device comprising a tool shaft, anon-reciprocating housing chamber which contains one end of said shaftand a motor mechanism to motivate said shaft, the improvement consistingof a safety attachment comprising an envelope of elastomeric rubber-likematerial having an opening in one end thereof of about the same shapeand cross-sectional area as the pneumatic tool shaft and an opening inthe other end thereof of about the same shape and cross-sectional areaas the housing chamber, the latter mentioned end of said envelope beingin much tighter engagement with the area it surrounds than is the firstmentioned end of said envelope with the area which it surrounds, andsaid safety attachment containing perforations intermediate the endsthereof to facilitate installation and removal from the pneumaticdevice.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 840,891 Adams Jan. 8, 1907 1,853,128 Hysing Apr. 12, 19322,117,880 Goddard May 17, 1938

